Use of STM during a mass or multi casualty incident (MCI)

The scoring of trauma patients done routinely by emergency responders facilitates quick scoring of patients at an MCI. Patients are then grouped by score ranges (similarly to how it is done typically with tag colors), and then patient transport priorities are set initially through the rule-based-protocol, and through STM software upon communication of scene and resource information. Steps are defined below:

Step 1. Scoring and tagging of victims

Victims are assessed and given an RPM score. Scores are computed as they are for routine trauma patients. Triage tags are used to attach the score to the victim. Scorecard or Personal Data Assistant (PDA) devices are used as a scoring reference.

Step 2. Organization of victims at the scene

Victims are organized at the scene into RPM groups. Groupings are determined a priori by the EMS jurisdiction, but a suggested grouping might be:

  • 0 – 1 Likely Expectant.
    Extremely low survival probability.
  • 2 – 4 Critical.
    Very low survival probability; likely rapid deterioration
  • 5 – 8 Compromised/Salvageable.
    Salvageable, but accelerating deterioration without definitive care.
  • 9 – 10 Delayed/Slow.
    High survival probability, with little deterioration expected in the first 60 minutes.
  • 11 – 12 Likely Minor.
    High survival probability, slow rate of deterioration.

(Note: The groupings can and should be adjusted to reflect local operating policy.)

The commonality within these groups of survivability and expected deterioration enable better use of scene and regional medical resources.

The initial triage from the scene, which can occur as patients are grouped, can be based on the rule-based triage strategy and is implemented prior to Step 3.

Step 3. Determining the optimal triage strategy with communications and technology support

At the onset of an incident, transport and treatment capacity and availability updates are input into the STM software. Victim scores and scene data are communicated to incident command or a dispatch facility as it is gathered, and the STM triage and resource management software is run on a laptop computer. The output is the Incident Action Plan (IAP) that includes the triage strategy that assigns victims in priority order by score to specific treatment facilities. The model balances and distributes the patient loads among facilities based on standard and surge capacities to mitigate the impact on any one facility. The planned impact and scheduled patient arrivals to every treatment facility is known immediately and communicated directed or through a secure web site to all treatment facilities. Expected survivorship is also known.

An overview of the software is provided in the schematic below:

The time for communication and inputting of scores, running of the optimization program, and communicating the triage strategy back to the scene takes less than one minute in simulations. Large scale incidents require periodic communication.

Step 3 (alternate) : Determining the triage strategy at incident onset or in the absence of communications or technology support

In the absence of communications or technology support, and at the onset of an incident, rules are used to triage patients. Rules are customized for the EMS operating jurisdiction, and provide a priority ordering of patients based on the incident commander’s assessment of the size and complexity of the scene, and the availability of resources. Rules are determined through simulations, and can be specific to specific threats that a region anticipates, and the regional resources typically available in response.

Step 4: Scene implementation of strategy (concurrent with step 5)

Victims are assigned to transport and to treatment facility as per the triage strategy. Deviations or changes in scene conditions are readily accepted in the model and may include the discovery or scoring of additional trauma victims, or changes in the plan as implemented by scene personnel. Changes are recorded (in the same way assignments are currently recorded at MCI scenes, typically through a “transport log”), communicated, and a revised triage strategy is determined.

Step 5: Resource management (concurrent with step 4)

Utilization of resources is tracked during the incident according to the plan, and updated to reflect incident and non-incident related changes in the availability of resources (e.g. a hospital experiencing a secondary incident might lose all available capacity to support this incident). For each treatment facility, we use three levels of capacity: routine capacity; initial surge capacity and time to surge; and max surge capacity and time to surge. These capacities are not violated in the assignment of victims unless the incident size exceeds the region’s available resources, and in tracking utilization the model includes an estimate of the time needed to provide life-saving care for each trauma patient. For transport capacity, we estimate the cycle time needed for a trip from the scene, to the assigned treatment facility, and the return to the scene including patient processing time.

Every incident, and every MCI exercise would follow these same steps, and each would be evaluated empirically against the objective of maximizing expected survivors. Whereas current MCIs and exercises are subjectively reviewed, STM exercises and events have measurable (projected) outcomes.